List and Params Keyword Queries

harish reddy

Hello, I have 2 questions as described below:

First Question:

I have List with a Variable named "Integers" which contain 1,2,3,4,5,6,7,8,9.

My requirement now is to store the set of 3 integers of the list in to either a new List or Array. Pls let me know how can i read the elements of the list and keep storing them in to a new list or array?

i should be able to store the first 3 elements in to a new list or array. The next 3 elements in to other list. The last 3 elements in to other list. Pls guide.

Second Question:

char[] c = { ',',':' };

string[] splittedStrings = item.Split(c);

In the above line, while writing the code,i was thinking it should be string[] splittedStrings = item.Split( params c). But writing "Params" in the arguemt is gving me the error. Pls guide why? In the VS it was showing (Params Char[] Seperator), hence the question. Pls guide.

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sachin Singh5y ago
Accepted answer
Answer to your 1st question:- below code will split your list into n number of list of 3 size ,
Note :- you can also use Enumerator and MoveNext which is a lengthy process.
static void Main(string[] args)
       {
           List nums = new List() { 1, 2, 3, 4, 5, 6, 7, 7, 8 };
           var list = Split(nums);
           foreach (var item in list)
           {
               foreach (var i in item)
               {
                   Console.WriteLine(i);
               }
               Console.WriteLine("another chunk of list starts from here");
           }
           Console.ReadLine();
       }

       public static List> Split(List source)
       {
           return source
               .Select((x, i) => new { Index = i, Value = x })
               .GroupBy(x => x.Index / 3)
               .Select(x => x.Select(v => v.Value).ToList()).ToList();

       }
Answer to 2nd Question:-
Params can only be used at the time of method declartion not while calling it, params allow you to paas any no of parameters as a comma separated value.
ex
public int Add(params int[] numbers){
    int sum=0;
    foreach(int i in numbers)
    {
      sum=sum+i;
    }
    }
    // you can call it like  Add(1,2,3,4,5) or Add(1,2) but not as Add(params 2,3)
Željko Perić5y ago
Hello https://www.c-sharpcorner.com/members/harish-reddy26

Here is interesting article that will help You to solve the first problem:

http://www.java2s.com/Tutorials/CSharp/System.Collections.Generic/List_T_/C_List_T_CopyTo_Int32_T_Int32_Int32_.htm

Second problem:

https://docs.microsoft.com/en-us/dotnet/api/system.string.split?redirectedfrom=MSDN&view=net-5.0#System_String_Split_System_Char___

All the best,
Željko Peric